Well, look what the cat dragged in: an other ethically crippled trial lawyer in a legislative leadership post.

That would be new state Senate Democratic leader John Sampson of Brooklyn — the pious hypocrite who slipped a knife in mayoral control of the city’s public schools even as he’s suing that very same system.

As The Post’s Jennifer Fermino reports today, Sampson — as a private lawyer — is suing Schools Chancellor Joel Klein on behalf of a former assistant principal who alleges wrongful dismissal.

This, while trying to strip Klein of his power over city schools in toto.

Conflict of interest?

Sure seems that way.

Such conflicts, of course, are nothing new in Albany.

Sampson’s client, former assistant principal Merlin Rosal-Hutchinson, was dismissed by her principal after allegedly neglecting her duties and verbally abusing a special-needs student — findings that were upheld on appeal.

Empowering principals to make such personnel decisions was one of the key early reforms under mayoral control — and one that’s sure to be imperiled under a revived Board of Education.

Under the old system, unaccountable borough presidents and community school boards regularly greased the wheels for insiders — as they very well might, say, for the client of a powerful Senate leader.

In the meantime, as we noted Monday, the transition back to Board of Education control is certain to be bathed in further lawsuits — to the great profit of . . . lawyers like John Sampson.